Before the deleveraging came the leveraging. Take the US. The ratio of all sorts of debt to GDP rose from 160 per cent in 1975 to 342 per cent at the end the September 2007. Through to 2000, debt increased by 2.4 percentage points a year faster than GDP. But after the turn of the millennium, the excess of debt growth accelerated almost to 3.7 percentage points a year. The pattern was similar but less extreme in the eurozone, and similar but more extreme in the UK.

While it was happening, only a few sourpusses complained. Leverage, it was said, was a natural trend. As economies get richer, they have more need for debt-financed investments and debt-financed inventories. But lending grew much faster after 2000 than even the most gifted apologist could explain away.